Ina conventional communication network, a transmission medium may be classified into two types: wired and wireless. A wireless transmission medium mainly includes a microwave line and a synchronous satellite line, and a wired transmission medium mainly includes a copper cable and an optical fiber cable. After the digital communication era comes, the copper cable cannot meet the requirements of the rapid development of digital communication due to the limitation of information capacity of the copper cable. The optical fiber cable has an information capacity several orders of magnitude greater than that of the copper cable. Therefore, the optical communication technology using the optical fiber cable as the transmission medium attracts more and more attentions of the industry.
The development of the optical communication technology poses higher and higher requirements on the performance of optical switches in an optical communication system. The optical switches are key components that are used to perform channel switching for optical signals in optical transmission lines, and may be widely used to implement functions such as route selection, wavelength selection, and optical cross-connection of an all-optical layer. Optical switches mainly include mechanical optical switches and waveguide optical switches. An optical switch based on the micro-electro-mechanical system (MEMS), hereinafter referred. The MEMS optical switches are becoming the mainstream of the optical switch technology because of the advantages such as low insertion loss, low power consumption, independence of wavelength and modulation mode, long life, and high reliability.
Ina conventional MEMS optical switch, a micro-mirror is placed above a semiconductor substrate (for example, a silicon substrate) by using a semiconductor manufacturing process. The micro-mirror can be set movably through a micro-mechanical structure so that the electronic, mechanical and optical functions are integrated in a chip. The basic working principle of the MEMS optical switch is as follows: the electrostatic or electromagnetic force drives the movable micro-mirror to ascend and descend, rotate, or move, so that an optical path is turned on or off by changing the light transmission direction.
In an existing MEMS optical switch, the latching of the optical switch status is generally implemented through a mechanical structure that uses the gear engagement or a combination of a clip and a buckle. However, the latching structure is complicated and occupies an unduly large chip area. Therefore, for the existing MEMS optical switch, it is difficult to implement an optical switch array with a plurality of micro-mirror arrays on a chip. In other words, it is difficult to achieve the large-scale integration.